Method and apparatus for screen object manipulation

ABSTRACT

The present invention comprises a method and apparatus for manipulating screen objects utilizing multiband regions of influence. Positioning a reference point of an object within a particular band invokes a particular functionality or operation related to that band. In one embodiment, three types of functionality are provided. Moving a reference datum (for example, a line representing an edge or a user defined reference point) of an object A into a first band of an object B places object A under the influence of object B&#39;s gravity, causing object A to be pulled into precise alignment with object B. Moving the reference point of object A from the first band into a second band turns off object B&#39;s gravity, allowing object A to be freely moved to any arbitrary position near the object B. Moving the reference point of the object A to a position outside all bands causes object B&#39;s gravity function to be turned back on. In other embodiments, the bands of the invention provide other kinds of functionalities or operations. For example, one embodiment comprises bands that provide different types of precise positioning. In one embodiment, multiple bands are provided, each one causing objects to be positioned so as to be spaced apart by one of several precise, predetermined distances.

This application is a Continuation of Ser. No. 11/077,822 filed Mar. 10,2005, which is a Continuation of Ser. No. 10/021,889 filed Dec. 12,2001, which is a Continuation of Ser. No. 09/584,836 filed May 31, 2000,now U.S. Pat. No. 6,337,703, which is a Continuation of Ser. No.09/004,233 filed Jan. 8, 1998, now U.S. Pat. No. 6,088,027.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the manipulation of objects displayedon a display screen, and more particularly to a method and apparatus forpositioning objects using direct manipulation.

2. Background Art

FIG. 1 shows an example of two objects, object A 100 and object B 105,displayed on a display device such as a computer display screen. Theobjects may, for example, be objects created with a graphics editingprogram. Objects such as object A 100 and object B 105 that aredisplayed on a display screen may 15 be referred to as “screen objects.”The screen objects shown in FIG. 1 are simple rectangles. However,screen objects can have any size and shape. Further, a screen object mayconsist of a group of different objects. For example, a screen objectmay comprise a bit-mapped image combined with a vector-based drawingobject. A screen object may also represent other objects or data, suchas, for example, a sound clip or video data.

A user often desires to manipulate screen objects such that they areprecisely located or precisely dimensioned with respect to other objectson the screen. For example, a user may desire to position an object suchthat one or 25 more of its edges coincide with one or more edges ofanother object, as shown in FIG. 2, or such that one or more of itsedges are positioned close to but spaced apart from another object, asshown in FIG. 3. A user may also wish to resize an object such that theobject has the same height and/or width as another object, as shown inFIG. 4.

A number of approaches to the precision location and precision sizing ofscreen objects have been developed in the prior art.

One approach, used in drawing programs such as MacDraw™ and ClarisWorks™, is to provide precision-location and precision-sizing commands.To use these commands, a user must first select the objects in question,for example by positioning a cursor over each object and clicking amouse button. Next, the user must invoke the desired command, forexample by hitting an appropriate hot key or key combination on akeyboard or by selecting the command using pull-down menus. Finally, theuser must enter information regarding the manner in which the user wantsto position or resize the object into a dialog box that opens after thecommand is activated. FIG. 5 shows an example dialog box for the “align”menu command from MacDraw™.

Although using precision location and precision sizing commands allowsthe user to position or size objects, the multiple steps required to usethese commands are inconvenient.

A second approach uses a technique sometimes referred to as “gravity.”In this approach an object, around its edges, is provided with a “regionof influence” that exerts a pull on other objects that come into theregion. FIGS. 6-9 illustrate the operation of the prior art gravitytechnique. In FIG. 6, a dotted rectangle 600 indicates the region ofinfluence for the left edge of object B 105. FIG. 6 also shows a mousecursor 605 positioned over object A 100. A user may move object A 100 byselecting and “dragging” object A 100 with a mouse.

In the gravity approach, when a first object (such as object A 100) isdragged so that one of its edges enters the region of influence of anedge of a second object (such as object B 105), the first object isautomatically “snapped” to the second object such that the edges of thetwo objects meet. FIG. 7 shows object A 100 after it has been movedhorizontally to the right such that its right edge enters region ofinfluence 600 of object B 105. Once the right edge of object A 100enters region of influence 600, object A 100 is snapped to the rightsuch that its right edge is aligned with the left edge of object B 105,as shown in FIG. 8. In this prior art example, if mouse cursor 605 isdragged far enough further to the right, object A 100 once again becomes“unstuck” from object B 105, as shown in FIG. 9.

Although the gravity technique of the prior art is useful when a userwants to align objects such that their edges coincide, it prevents theuser from arbitrarily positioning objects close to one another. As soonas an edge of a first object enters a second object's region ofinfluence, the first object is snapped into alignment with the secondobject. Prior art gravity systems thus provide for easy alignment, butat the cost of preventing arbitrary positioning of objects close to oneanother.

SUMMARY OF THE INVENTION

The present invention comprises a method and apparatus for manipulatingscreen objects utilizing multiband regions of influence. Positioning areference datum of an object within a particular band invokes aparticular functionality or operation related to that band and to thatdatum.

In one embodiment, three types of functionality are provided. Moving areference point or datum (for example, a line representing an edge or auser-defined reference point) of an object A into a first band of anobject B places object A under the influence of object B's gravity,causing object A to be pulled into precise alignment with object B.Moving the reference point of object A from the first band into a secondband turns off object B's gravity, allowing object A to be freely movedto any arbitrary position near the object B. Moving the reference pointof the object A to a position outside all bands causes object B'sgravity function to be turned back on. By providing multiple bands offunctionality, this embodiment allows a user to conveniently selectamong precise positioning (or sizing) provided by gravity and arbitrarypositioning (or sizing) allowed by an absence of gravity, simply bydragging an object's reference point into an appropriate band. No menucommands are required.

In other embodiments, the bands of the invention provide other kinds offunctionalities or operations. For example, one embodiment comprisesbands that provide different types of precise positioning. In oneembodiment, multiple bands are provided, each one causing objects to bepositioned so as to be spaced apart by one of several precise,predetermined distances.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first arrangement of two example screen objects.

FIG. 2 shows a second arrangement of the screen objects of FIG. 1.

FIG. 3 shows a third arrangement of the screen objects of FIG. 1.

FIG. 4 shows a fourth arrangement of the screen objects of FIG. 1.

FIG. 5 shows a dialog box of an alignment command of the prior art.

FIG. 6 shows an example of a region of influence of the prior art.

FIG. 7 shows the operation of the region of influence of FIG. 6.

FIG. 8 shows the operation of the region of influence of FIG. 6.

FIG. 9 shows the operation of the region of influence of FIG. 6.

FIG. 10 shows an embodiment of a multiband region of influence of theinvention.

FIG. 11 shows an example of a reference datum for an object being movedin one embodiment of the invention.

FIG. 12 shows the operation of the multiband region of influence of FIG.10.

FIG. 13 shows the operation of the multiband region of influence of FIG.10.

FIG. 14 shows the operation of the multiband region of influence of FIG.10.

FIG. 15 shows a state transition model for one embodiment of theinvention.

FIG. 16 shows an embodiment of a multiband region of influence of theinvention.

FIG. 17 shows an embodiment of a multiband region of influence of theinvention.

FIG. 18 shows an embodiment of a multiband region of influence of theinvention.

FIG. 19 shows an embodiment of a multiband region of influence of theinvention.

FIG. 20 shows how datum lines for an object being moved are determinedin one embodiment of the invention.

FIG. 21 shows how datum lines for an object being moved are determinedin one embodiment of the invention.

FIG. 22 shows how datum lines for an object being moved are determinedin one embodiment of the invention.

FIG. 23 shows the operation of one embodiment of a multiband region ofinfluence of the invention.

FIG. 24 shows the operation of one embodiment of a multiband region ofinfluence of the invention.

FIG. 25 shows the operation of one embodiment of a multiband region ofinfluence of the invention.

FIG. 26 shows the operation of one embodiment of a multiband region ofinfluence of the invention.

FIG. 27 is an example of one embodiment of a computer system that can beused to implement the invention.

FIG. 28 is a flow chart showing the operation of one embodiment of theinvention.

FIG. 29 shows an example of a datum line used with an embodiment of amultiband region of influence of the invention when an object is beingresized.

FIG. 30 shows an example of the user interface of a sound editingprogram that uses an embodiment of the invention.

FIG. 31 shows an example of how the reference datum and regions ofinfluence of the invention may be used with the embodiment of FIG. 30.

FIG. 32 shows an example of non-rectilinear objects used with anembodiment of the invention.

FIG. 33 illustrates the operation of the embodiment of FIG. 32.

DETAILED DESCRIPTION OF THE INVENTION

A method and apparatus for manipulation of screen objects is described.In the following description, numerous specific details are set forth inorder to provide a more thorough description of the invention. It willbe apparent, however, to one skilled in the art, that the invention maybe practiced without these specific details. In other instances,well-known features have not been described in detail so as not toobscure the invention.

FIG. 10 shows an example embodiment of a multiband region of influenceof the invention. In FIG. 10, a multiband region of influence 1001comprising bands 1005, 1010 and 1015 is shown extending outwardsadjacent to left edge 1045 of a first screen object B 1000. Dotted linesare used to show multiband region of influence 1001 in FIG. 10 toindicate that multiband region of influence 1001 is not normallydisplayed to a user. FIG. 10 also shows a second screen object A 1030located to the left of object B 1000, and a horizontal coordinate axis1020. Coordinate axis 1020 is provided to indicate relative horizontalpositions. For example, the right edge 1040 of object A 1030 is locatedat coordinate “eA” on axis 1020, while the left edge 1045 of object B1000 is located at coordinate “eB.” For the example of FIG. 10, object A1030 is initially constrained to move horizontally only. However, nosuch constraints are necessary to practice the invention.

In the example of FIG. 10, multiband region of influence is associatedwith an edge, namely left edge 1045, of object B 1000. However, in otherembodiments, the multiband region of influence of the invention may beassociated with other reference points of a screen object, includinguser defined reference points.

In the example of FIG. 10, multiband region of influence 1001 comprisesthree bands 1005, 1010 and 1015, respectively. As shown in FIG. 10, band1015 extends outwards a distance ks from left edge 1045 of object B1000. The right edge of band 1015 is thus located at coordinate “eB” oncoordinate axis 1020, while the left edge of band 1015 is located atcoordinate “eB−ks.” Band 1010 extends from the left edge of band 1015 atcoordinate “eB−ks” to coordinate “eB−ku.” Band 1005 extends from theleft edge of band 1010 at coordinate “eb−ku” to coordinate “eB−kr.”

In the example of FIG. 10, object A 1030 is to be moved adjacent toobject B 1000, for example by “drag and dropping” with a mouse. To dragand drop object A, a mouse is used to position a cursor 1050 over objectA 1030. A mouse button is then depressed, locking the cursor onto objectA 1030 at the spot at which the mouse button was depressed. The cursoris then moved to a new location, “dragging” object A with it. At the newlocation, the mouse button is released, thereby “dropping” object A 1030at the new location.

The process of dragging and dropping an object may be displayed to auser in a number of ways, depending on the embodiment of the userinterface being used. In certain embodiments, the object is shown tomove with the cursor in real time. In other embodiments, the objectremains in place, and an outline representing the object moves with thecursor to indicate the object's new location. For the process of theinvention, any representation of drag-and-dropping may be used.

In one embodiment, a reference datum representing the position of one ormore edges of an object being moved with respect to a cursor location isused to determine whether the functionality associated with a multibandregion of influence is to be invoked. In other embodiments, other and/oradditional reference datums may be used. In one embodiment, the user maydefine reference datums for a screen object. Different functionalitiesmay be associated with different datums, or with different ways ofselecting a datum. For example, selecting a datum by clicking a leftmouse button may invoke a different functionality, when the datum ismoved inside a region of influence, than selecting the datum by clickinga right mouse button. In one embodiment, for an object having multiplereference datums, the datum closest to the cursor position when themouse button is clicked is deemed to be the active datum whose positionrelative to a region of influence invokes the functionality associatedwith the region.

In FIG. 10, at the time the mouse button is depressed, cursor 1050 islocated on object A 1030 at coordinate “m0” on horizontal coordinateaxis 1020. Since the right edge 1040 of object A 1030 is located atcoordinate “eA,” the horizontal distance of right edge 1040 from cursor1050 at this time is Δa=eA−m0. Right edge 1040 of object A 1030 is thuslocated a distance Δa to the right of cursor 1050.

FIG. 11 shows mouse cursor 1050 after it has moved horizontally to theright from its position at coordinate “m0” in FIG. 10 to coordinate “m”on coordinate axis 1020. Reference datum 1100 represents a referencedatum for right edge 1040 of object A 1030. Since right edge 1040 ofobject A 1030 was located a distance Δa to the right of cursor 1050 whenthe mouse button was depressed, reference datum line 1100 is defined tobe located at horizontal coordinate “m+Δa” when the mouse cursor ispositioned at horizontal coordinate m.

As mouse cursor 1050 is moved, the value of its horizontal coordinate“m” is monitored. Using this value, the coordinate “m+Δa” for referencedatum line 1100 is calculated. The value of coordinate “m+Δa” iscompared to the coordinates of the edges of bands 1005, 1010 and 1015 ofregion of influence 1001 to determine whether any functionality relatedto region of influence 1001 is to be applied. FIGS. 12, 13 and 14illustrate how reference datum line 1100 falls successively into bands1005, 1010, and 1015 of multiband region of influence 1001 as cursor1050 is moved to the right. As shown in FIG. 12, reference datum line1100 falls into band 1005 when (eB−kr)<(m+Δa)<(eB−ku). As shown in FIG.13, reference datum line 1100 falls into band 1010 when(eB−ku)<(m+Δa)<(eB−ks). And as shown in FIG. 14, reference datum line1100 falls into band 1015 when (eB−ks)<(m+Δa)<eB.

The bands of the region of influence of the invention can have a varietyof configurations. Bands may be contiguous as in the embodiment of FIG.10. Alternatively, they may overlap, be separated, or be arranged insome other manner. Bands may be associated with one or more externalboundaries of an object, and/or with one or more other external orinternal points or features of an object. For example, in one embodimentthat allows a user to establish multiple user-defined reference datumsfor an object, bands of influence may be associated with each of theuser-defined reference datums.

The multiband regions of influence of the invention can be used toinvoke a variety of functionalities, depending on the embodiment. In oneor more embodiments, the particular functionality invoked may depend notonly on the location of a reference datum, but also on the identity andtype of the datum, on the type of operation being performed (e.g.moving, resizing, etc.), on the direction of datum line movement, onwhether the right or left mouse button has been clicked or a keyboardkey has been depressed, on the states of objects being manipulated,and/or on other criteria. The functionality invoked by a region ofinfluence of the invention may apply an action to an object or objects,may invoke a change of an object or objects from one state to another,or may apply some other function or action.

For example, in one embodiment, as shown in FIG. 15, there are threepossible states when one object (“object A”) is being dragged withrespect to another object (“object B). In state 1 1500, object B's“gravity” is turned on. However, object A is located outside of objectB's region of influence and is therefore freely movable (not stuck toobject B). In state 2 1510, object A, under the influence of object B'sgravity, has become stuck to object B. In state 3, object B's gravityhas been turned off, and object A, accordingly, is not stuck to object Band is freely movable even within object B's region of influence.

In the state model of FIG. 15, there are three possible statetransitions: (i) from state 1 to state 2 (object A falls within pull ofobject B's gravity and becomes stuck to object B); (ii) from state 2 tostate 3 (object B's gravity is turned off, allowing object A to movefreely in vicinity of object B); and (iii) from state 3 to state 1(object B's gravity is turned back on, object A being outside object B'sregion of influence).

The state transitions of the embodiment of FIG. 15 may be associatedwith the multiband regions of influence of the invention in a variety ofways. The state transitions of the embodiment of FIG. 15 may, forexample, be associated with bands 1005, 1010 and 1015 of FIG. 14.

In one embodiment, the associations between the state transitions andbands 1005, 1010 and 1015 are as follows:

-   -   1. When reference datum line 1100 of object A 1030 is outside        object B 1000's region of influence 1001 (i.e. datum line 1100        is not in any of bands 1005, 1010 or 1015), as shown in FIG. 11,        object A is in state 1. In state 1, eA=m+Δa.    -   2. A transition from state 1 to state 2 occurs in band 1015, the        band closest to object B 1000. Object A 1030 thus stays in state        1 until cursor 1050, as shown in FIG. 14, is moved such that        datum line 1100 enters band 1015 (i.e. (m+Δa)>eB−ks). At this        point, object A 1030 transitions to state 2, becoming stuck to        object B 1000 such that right edge 1040 of object A 1030        coincides with left edge 1045 of object B 1000. In state 2,        therefore, eA=eB.    -   3. A transition from state 2 to state 3 occurs in band 1005. To        turn off object B 1000's gravity such that object A 1030 becomes        unstuck and freely positionable near object B 1000, cursor 1050        must be moved such that datum line 1100 enters band 1005. Once        the transition from state 2 to state 3 has occurred, datum line        1100 can be moved back into band 1015 without object A 1030        becoming stuck to object B 1000.    -   4. A transition from state 3 back to state 1 occurs beyond the        outermost band of region of influence 1001. If object A 1030 is        in state 3 (unstuck, object B 1000's gravity off), and it is        desired for object A 1030 to be stuck to object B 1000, datum        line 1100 must first be moved beyond the outermost band (i.e.        band 1005) of region of influence 1001 (to turn object B 1000's        gravity back on), and then back inside band 1015 (such that        object A 1030 becomes stuck to object B 1000 under the influence        of object B 1000's gravity).

In this embodiment, no state transitions or other functionality isassociated with band 1010. Accordingly, the same functionality can beprovided by the multiband region of influence 1600 of FIG. 16, whichincludes two bands 1605 and 1610 spaced apart by a distance of ku−ks.

In the embodiments of FIGS. 10 and 16, objects were constrained to movehorizontally and a multiband region of influence of the invention wasshown to extend outwardly in only one direction from only one edge of ascreen object. In the more general case, objects may be moved in anydirection, and the multiband region of influence extends to both sidesof each edge of a screen object. FIGS. 17-19 show different exampleconfigurations of the multiband region of influence of the invention.

In the embodiment of FIG. 17, multiband region of influence 1700, likemultiband region of influence 1600 of FIG. 16, comprises two bands 1705a and 1710 a extending to the left of left edge 1045 of object B 1000.In addition, multiband region of influence 1700 includes two bands 1710b and 1705 b extending to the right of edge 1045. In this embodiment,bands 1710 b and 1705 b are mirror images of bands 1710 a and 1705 a,respectively, and have the same associated functionalities.

In the embodiment of FIG. 18, multiband region of influence 1800consists of two bands 1805 and 1810 to the left of left edge 1045 ofobject B 1000 and one band 1815 to the right of edge 1045. In thisembodiment, each of the bands 1805, 1810 and 1815 may have differentassociated functionalities. In one embodiment, for example, using thestate model of FIG. 15, band 1810 invokes a transition from state 1 1500to state 2 1510, while band 1815 invokes a transition from state 2 1510to state 3 1520, and band 1805 invokes a transition from state 3 1520 tostate 1 1500.

FIG. 19 shows an object 1900 that has multiband regions of influence1910, 1920, 1930, and 1940 associated with each of its sides 1915, 1925,1935 and 1945, respectively. Each multiband region of influence1910-1940 includes six bands a, b, c, d, e and f. The bands invokecertain specified functionalities on objects whose datum lines enterinto one or more of the bands. Objects in the embodiment of FIG. 19 arenot constrained to move horizontally or vertically, but can move in anydirection. In one embodiment, using the state model of FIG. 15, bands cand d invoke a transition from state 1 1500 to state 2 1510, bands a andf invoke a transition from state 2 to state 3, and the region outside ofbands a-f invokes a transition from state 3 to state 1. In thisembodiment, bands b and e do not invoke any functionality.

FIGS. 20 and 21 show how datum lines are established for use withmultiband regions of influence in one embodiment of the invention. FIG.20 shows an object 2000 with left edge 2005, bottom edge 2010, rightedge 2015, and top edge 2020. The datum lines are established, forexample, when a mouse cursor is positioned over an object and a mousebutton is pressed and held.

FIG. 20 shows a mouse cursor 2025 after it has been positioned overobject 2000 and its mouse button has been pressed. At the moment themouse button is pressed, the distance of cursor 2025 from each of theedges 2005, 2010, 2015 and 2020 is determined. As shown in FIG. 20, thedistances from cursor position 2025 to each of edges 2005, 2010, 2015and 2020 at the time the mouse button is pressed are Δa, Δb, Δc and Δd,respectively.

Datum lines are established at locations that correspond to the positionof edges 2005, 2010, 2015 and 2020 relative to cursor position 2025 atthe time the mouse button is pressed, as shown in FIG. 21. FIG. 21 showscursor 2025 after it has been moved, keeping the mouse button pressed,from its original position in FIG. 20. As shown in FIG. 21, the datumlines for edges 2005, 2010, 2015 and 2020 move along with cursor 2025 ascursor 2025 is dragged to a new position. In FIG. 21, datum line 2105corresponds to edge 2005, datum line 2110 corresponds to edge 2010,datum line 2115 corresponds to edge 2015, and datum line 2120corresponds to edge 2020.

In the embodiment FIG. 21, the length of each datum line is the same asthe length of the corresponding edge of object 2000. However, in otherembodiments, the length of a datum line may be different from the lengthof the corresponding object edge. For example, in FIG. 22, datum lines2105, 2110, 2115 and 2120 extend indefinitely.

FIGS. 23-26 demonstrate the interaction of the datum lines of FIG. 21with the multiband regions of influence of FIG. 19 in one embodiment ofthe invention. In the embodiment of FIGS. 23-26, the functionalityinvoked by regions of influence related to vertical edges of objects isinvoked only if all or part of a vertical datum line of an object beingmoved falls into the region, while the functionality invoked by regionsof influence related to horizontal edges of objects is invoked only ifall or part of a horizontal datum line of an object being moved fallsinto the region.

For example, in FIG. 23, cursor 2025, originally positioned on object2000 as shown in FIG. 20, has been moved, along with the datum lines2105, 2110, 2115, and 2120 such datum line 2120 (corresponding to topedge 2020 of object 2000) protrudes into band 1930 d of multiband regionof influence 1930 (relating to bottom edge 1935 of object 1900), anddatum line 2105 (corresponding to left edge 2005 of object 2000)protrudes into band 1910 c of multiband region of influence 1910(relating to left edge 1915 of object 1900).

In the embodiment of FIG. 23, using the state model of FIG. 15, bands cand d of each region of influence invoke a transition from state 1 1500to state 2 1510, bands a and f invoke a transition from state 2 1510 tostate 3 1520, and the region outside of bands a-f invokes a transitionfrom state 3 1520 to state 1 1500. In this embodiment, bands b and e donot invoke any functionality. Accordingly, when cursor 2025 of FIG. 20is located as shown in FIG. 23:

-   -   1. Because datum line 2120 protrudes into band 1930 d, a change        in state from state 1 1500 to state 2 1510 is invoked with        respect to bottom edge 1935 of object 1900 and top edge 2020 of        object 2000. If the mouse button is released while cursor 2025        is in this position, the top edge 2020 of object 2000 becomes        “stuck” (aligned), in a vertical direction, to the bottom edge        1935 of object 1900.    -   2. Because datum line 2105 protrudes into band 1910 c, a change        in state from state 1 1500 to state 2 1510 is invoked with        respect to left edge 1915 of object 1900 and left edge 2005 of        object 2000. If the mouse button is released while cursor 2025        is in this position, left edge 2005 of object 2000 becomes        “stuck” (aligned), in a horizontal direction, to the left edge        1915 of object 1900.

The resulting placement of object 2000 with respect to object 1900 isshown in FIG. 24.

A user may, however, desire to turn off the gravity associated with oneor more edges of object 1900 so that one or more edges of object 2000can be placed close to one or more sides of object 1900 without beingstuck to that side. In the embodiment of FIG. 23, gravity with respectto an edge of object 1900 is turned off by moving the appropriate datumline from band c or d into band a or f of the multiband region ofinfluence associated with that edge. For example, to turn off thegravity with respect to left edge 1915 of object 1900, cursor 2025 ismoved from the location shown in FIG. 23, at which datum line 2105extends into band 1910 c, to the location shown in FIG. 25, at whichdatum line 2105 extends into band 1910 a, thereby causing the gravityassociated with left edge 1915 of object 1900 to be turned off. Ifcursor 2025 is now moved back to the location shown in FIG. 23, and themouse button released, top edge 2020 of object 2000 will still be stuck,in a vertical direction, with bottom edge 1935 of object 1900 (becausegravity with respect to bottom edge 1935 is still on, and datum line2120, corresponding to top edge 2020 of object 2000 still extends intoband 1930 d). However, because gravity associated with left edge 1915 ofobject 1900 has been turned off, left edge 2005 object 2000 will notbecome stuck to left edge 1915 of object 1900 even though datum line2105 extends into band 1910 c. Instead, left edge 2005 of object 2000will be located at the same horizontal position as the horizontalposition of datum 2105 in FIG. 23. The resulting position of object 2000with respect to object 1900 is shown in FIG. 26.

The present invention can be implemented by means of softwareprogramming on any of a variety of one or more computer systems as arewell known in the art, including, without limitation, computer systemssuch as that shown in FIG. 27. The computer system shown in FIG. 27includes a CPU unit 2700 that includes a central processor, main memory,peripheral interfaces, input-output devices, power supply, andassociated circuitry and devices; a display device 2710 which may be acathode ray tube display, LCD display, gas-plasma display, or any othercomputer display; an input device 2730, which may include a keyboard,mouse, digitizer, or other input device. The computer system may or maynot include non-volatile storage 2720, which may include magnetic,optical, or other mass storage devices, and a printer 2750. The computersystem may also include a network interface 2740, which may consist of amodem, allowing the computer system to communicate with other systemsover a communications network such as the Internet. Any of a variety ofother configurations of computer systems may also be used.

FIG. 28 is a flow chart showing the operation of one embodiment of theinvention. As shown in FIG. 28, the activation of a mouse button isawaited at step 2805. When a mouse button is activated, notification ofthe mouse button activation is received at step 2810. At step 2815, adetermination is made as to whether the mouse cursor is positioned overan object (such as, for example, object 2000 of FIG. 20) on a displayscreen. If it is determined that the cursor is not positioned over anobject, processing returns to step 2805.

If it is determined that the cursor is positioned over an object, theidentity and location of the applicable reference datum is determined atstep 2820. For example, for an object for which no other referencedatums other than its external boundaries have been established, in oneembodiment, the applicable reference datum will be the object's externalboundaries. Alternatively, if the object has other reference datumsother than its external boundaries, one or more applicable datums aredetermined using appropriate criteria. In one embodiment, for example,the reference datum nearest the cursor position when the mouse button isclicked is selected as the applicable datum. A variety of other criteriamay also be used.

At step 2825, the initial state of the object at the time the mousebutton is clicked is determined. In one embodiment, the initial state isdeemed to be state 3 of FIG. 15: namely, the object is not currentlystuck to any other object, and the gravity associated with anyimmediately adjacent object is off. In another embodiment, the initialstate of the object is the state of the object that resulted from anyimmediately prior manipulation of the object. For example, if the objectwas previously manipulated so as to become stuck to another object(state 2), then the initial state at step 2825 is also state 2. In otherembodiments, other criteria may be used to establish the initial state.

At step 2830, further mouse operations are monitored. At step 2835, adetermination is made as to whether the mouse has moved. If not, at step2840, a determination is made as to whether the mouse button has beenreleased. If the mouse button has been released, the current state ofthe object is determined at step 2843, and the object is redrawn at theappropriate location determined by the position of the cursor and thecurrent state at step 2845. If the mouse button has not been released,processing returns to step 2830.

If a determination is made at step 2835 that the mouse has moved, adetermination is made whether any applicable reference datum has enteredan applicable band of a multiband region of influence at 2850. Such adetermination may be made, for example, by determining whether the areference datum identified at block 2820 falls in an applicable band. Inone embodiment, if the applicable datum comprises the vertical andhorizontal edges of the external boundary of a rectangular object, anapplicable band is a band related to a vertical side of a stationaryobject for the vertical portions of the reference datum for an objectbeing moved, and a band related to a horizontal side of a stationaryobject for the horizontal portions of the datum for the object beingmoved. If it determined that no reference datum has entered anapplicable band, processing returns to step 2830.

If it is determined at step 2850 that a reference datum has entered intoan applicable band, then the current state for that band and that datumis determined at block 2855. The current state may, for example, bemaintained in a look-up-table listing objects, datums, and states. Thecurrent state may, for example, be one of the states of FIG. 15.

At step 2860, a determination is made as to whether the event of thedatum entering the band necessitates a change in state. Whether or not achange in state is required depends on the current state and theparticular band the datum has entered. For example, in the embodiment ofFIG. 19, if the current state is state 1 1500 of FIG. 15, and a verticaldatum line of the object being moved has entered band 1910 a, 1910 b,1910 e, or 1910 f, for example, no change in state is needed. However,if a vertical datum line of an object in state 1 enters into either ofbands 1910 c or 1910 d, a change in state is invoked from state 1 tostate 2.

If no change in state is required, processing returns to step 2830. If achange in state is required, that change is made and the new staterecorded at step 2865. Processing then returns to step 2830.

FIG. 29 shows an example of a datum 2910 used with the multiband regionof influence of the invention when an object is being resized, asopposed to being moved. To resize an object, a cursor 2915 is used toselect an edge (or in some embodiments a resizing “handle”) 2925 of theobject 2935 being resized. Only the edge 2925, not the entire object2935, moves when the edge is dragged to a new desired position. Datumline 2910 is located at the mouse cursor position and extends parallelto the edge 2925 that has been selected for resizing. The location ofedge 2925 once the mouse button is released during resizing isdetermined from current state of edge 2925 in relation to a multibandregion of influence and the position of the datum line 2910 at the timethe mouse button is released in the same manner as the location for theedge of an object being moved is determined as described with respect toFIGS. 19-26. However, in the case of resizing, instead of the objectbeing moved to match the new edge position, the object is stretched (orcompressed) to accommodate the new edge position.

FIG. 30 shows an example of the user interface of a sound editingprogram that uses an embodiment of the invention. FIG. 30 shows adisplay screen 3000 that contains two audio tracks 3001 and 3002. Thehorizontal axis of display screen 3000 represents time. Audio track 3001contains a screen object 3005 that represents a first sound clip. Audiotrack 3002 contains a screen object 3010 that represents a second soundclip. The relative horizontal positions of screen objects 3005 and 3010represent the points in time during which the sound clips represented bythe screen objects play during playback.

Screen object 3005 includes a name area 3015, a wave area 3025, and async point area 3020. Screen object 3010 also includes a name area 3045,a wave area 3050, and a sync point area 3040.

Name area 3015 displays the name of the sound clip represented by screenobject 3005. Wave area 3025 shows a representation of the sound waverepresented by screen object 3005. Sync point area 3020 showsuser-created sync points, such as sync point 3030. In one embodiment, auser may create a sync point by clicking in the sync point area of ascreen object at the desired horizontal location of the sync point andactivating an appropriate pull-down menu command.

In the embodiment of FIG. 30, screen objects 3005 and 3010 may be moved,using a pointing device such as a mouse, horizontally along audio tracks3001 and 3002, respectively. Screen objects may also be moved from onetrack to another. In one embodiment, a screen object may be moved bypositioning a mouse cursor in either the name area or the sync area, anddragging the object to the desired location. A screen object can beconstrained to remain in a track by, for example, holding down a shiftkey on a keyboard while dragging.

When a screen object is being moved in the example of FIG. 30, multibandregions of influence are activated with respect to each vertical sideand each sync point of the other screen objects displayed on the screen,as shown in FIG. 31. In FIG. 31, screen object 3005 is being moved.Accordingly, multiband regions of influence 3130, 3120, and 3125 areactivated with respect to the left and right edges and sync point 3035of screen object 3010, respectively.

In the embodiments of FIGS. 30 and 31, the applicable reference datumfor the screen object being moved is determined by the location of themouse cursor when the drag operation is begun (i.e. when the mousebutton is clicked). In the embodiment of FIGS. 30 and 31, a screenobject drag operation can be begun by positioning the cursor in eitherthe name area or the sync point area of the screen object being dragged.If the cursor is positioned in the name area of the screen object at thebeginning of a drag operation, the left or right edge of the screenobject that is nearest to the cursor position establishes the referencedatum applicable to that drag operation. If the cursor is positioned inthe sync point area, the nearest sync point establishes the referencedatum.

For example, in the embodiment of FIG. 31, if, at the beginning of adrag operation, the cursor is located at position 3100 in name area 3015of screen object 3005, the nearest left or right edge of screen object3005 is the left edge. Accordingly, reference datum 3105 is establishedat the horizontal location of the left edge of screen object 3005.Alternatively, if, at the beginning of a drag operation, the cursor islocated at position 3110 in sync point area 3020, the nearest sync pointis sync point 3030. Accordingly, reference datum 3115 is established atthe horizontal location of sync point 3030. The interaction of referencedatums 3105 or 3115 with multiband regions of influence 3130, 3125, and3120 allows an edge or sync point of one screen object to be preciselyaligned with an edge or sync point of another screen object, or to bepositioned close to but not precisely aligned with an edge or sync pointof the other screen object, as desired by the user, in the same manneras described with respect to the other embodiments of the invention.

FIGS. 32 and 33 show examples of non-rectilinear objects used in oneembodiment of the invention. FIG. 32 shows a stationary non-rectilinearobject 3200 and a moving non-rectilinear object 3220. In the example ofFIG. 32, object 3200 is an oval and object 3220 is a circle. However,objects 3200 and 3220 can have any arbitrary shape. In the example ofFIG. 32, stationary object 3200 has an associated multiband region ofinfluence 3210. Moving object 3220 has an associated reference datum3230, which may, for example, have been designated by a user. Multibandregion of influence 3210 comprises bands 3212, 3214 and 3216 which may,for example, have the same functionality as bands 1805, 1810 and 1815,respectively, of the embodiment of FIG. 18. FIG. 32 shows object 3220being moved towards object 3200, for example by being dragged with amouse.

According to the invention, if object 3220 is moved such that referencedatum 3230 enters band 3214 of multiband region of influence 3210,object 3200's gravity is turned on, and object 3220 is pulled towardsobject 3200 such that reference datum 3230 of object 3220 coincides withthe outside edge (i.e. the periphery) of stationary object 3200.Position “A” in FIG. 33 indicates the resulting relative positions ofobjects 3200 and 3220. If, for example, a user now drags object 3220 tothe left in a generally horizontal direction, object 3220 will remainstuck to object 3200 and move along the periphery of object 3200 (e.g.from position “A” to position “B”) as long as the conditions for object3220 being “stuck” to object 3200 (e.g. reference datum 3230 remains inband 3214 of multiband region of influence 3210) continue to be met.However, as in the embodiment of FIG. 18, if object 3220 is moved suchthat reference datum 3230 enters band 3216, object 3200's gravity isturned off, and object 3220 becomes unstuck from object 3200.

Thus, a method and apparatus for manipulating screen objects has beendescribed. Although the invention has been described with respect tocertain example embodiments, it will be apparent to those skilled in theart that the present invention is not limited to these specificembodiments. For example, although the multiband region of influence hasbeen described with respect to two-dimensional, rectangular screenobjects, the multiband region of influence of the invention can be usedwith three dimensional screen objects and with objects of any shape.Further, although the operation of certain embodiments has beendescribed in detail using certain detailed process steps, some of thesteps may be omitted or other similar steps may be substituted withoutdeparting from the scope of the invention. Other embodimentsincorporating the inventive features of the invention will be apparentto those skilled in the art.

The invention claimed is:
 1. A computer-implemented method formanipulating objects displayed on a display screen, comprising:providing a first screen object with a multiband region of influencecomprising a plurality of bands for invoking operations related tomanipulating screen objects displayed on said display screen;determining that a reference datum of a second screen object hasprotruded into a first band of said plurality of bands while themultiband region of influence of said first screen object is in an onstate; in response to determining that the reference datum of the secondscreen object has protruded into the first band, invoking a particularoperation that places one or more restrictions on movement of saidsecond screen object within the first band of influence; subsequent toinvoking the particular operation, determining that the reference datumof the second screen object is moved from the first band into a secondband of said plurality of bands; in response to determining that thereference datum of the second screen object is moved from the first bandinto the second band, transitioning the multiband region of influence ofthe first screen object to an off state wherein the one or morerestrictions on movement of said second screen object in the first bandof influence do not affect the second screen object when at least aportion of the second screen object is subsequently moved into saidfirst band of influence while the multiband region of influence remainsin said off state; subsequent to said enabling the second screen objectto move within said first band of influence without being restricted bysaid one or more restrictions, determining that the reference datum isagain moved outside of said first band and into said second band; inresponse to determining that the reference datum is again moved outsideof the first band and into the second band, returning the multibandregion of influence of the first screen object to said on state; and inresponse to returning the multiband region of influence of the firstscreen object to said on state, performing said particular operation asecond time and placing said one or more restrictions on movement ofsaid second screen object within the first band of influence.
 2. Thecomputer-implemented method of claim 1, wherein invoking said particularoperation comprises aligning said second screen object with respect tosaid first screen object.
 3. The method of claim 2, wherein in responseto said aligning, at least one edge of the second screen objectcoincides with at least one edge of the first screen object.
 4. Thecomputer-implemented method of claim 1, wherein each of said pluralityof bands comprises a defined two-dimensional area of said displayscreen.
 5. The method of claim 1, wherein invoking said particularoperation comprises joining said second screen object with the firstscreen object.
 6. The method of claim 1, wherein said first band andsaid second band are separated by a third band of said plurality ofbands.
 7. The method of claim 1, wherein said second band is larger thansaid first band.
 8. The method of claim 7, wherein said second bandwholly contains said first band.
 9. A program storage device readable bya machine, tangibly embodying a program of instructions executable bythe machine to perform a computer-implemented method for manipulatingobjects displayed on a display screen, comprising: providing a firstscreen object with a multiband region of influence comprising aplurality of bands for invoking operations related to manipulatingscreen objects displayed on said display screen; determining that areference datum of a second screen object has protruded into a firstband of said plurality of bands while the multiband region of influenceof said first screen object is in an on state; in response todetermining that the reference datum of the second screen object hasprotruded into the first band, invoking a particular operation thatplaces one or more restrictions on movement of said second screen objectwithin the first band of influence; subsequent to invoking theparticular operation, determining that the reference datum of the secondscreen object is moved from the first band into a second band of saidplurality of bands; in response to determining that the reference datumof the second screen object is moved from the first band into the secondband, transitioning the multiband region of influence of the firstscreen object to an off state wherein the one or more restrictions onmovement of said second screen object in the first band of influence donot affect the second screen object when at least a portion of thesecond screen object is subsequently moved into said first band ofinfluence while the multiband region of influence remains in said offstate; subsequent to said enabling the second screen object to movewithin said first band of influence without being restricted by said oneor more restrictions, determining that the reference datum is againmoved outside of said first band and into said second band; in responseto determining that the reference datum is again moved outside of thefirst band and into the second band, returning the multiband region ofinfluence of the first screen object to said on state; and in responseto returning the multiband region of influence of the first screenobject to said on state, performing said particular operation a secondtime and placing place said one or more restrictions on movement of saidsecond screen object within the first band of influence.
 10. The storagedevice of claim 9, wherein invoking said particular operation comprisesaligning said second screen object with respect to said first screenobject.
 11. The storage device of claim 10, wherein in response to saidaligning, at least one edge of the second screen object coincides withat least one edge of the first screen object.
 12. The storage device ofclaim 9, wherein each of said plurality of bands comprises a definedtwo-dimensional area of said display screen.
 13. The storage device ofclaim 9, wherein said second band is larger than said first band. 14.The storage device of claim 13, wherein said second band wholly containssaid first band.
 15. The storage device of claim 9, wherein invokingsaid particular operation comprises joining said second screen objectwith the first screen object.
 16. The storage device of claim 9, whereinsaid first band and said second band are separated by a third band ofsaid plurality of bands.